The instant Nina brings her boot to Anna’s face, Anna begins to shake her head around desperately trying to avoid inhaling the rather potent smell. Nina giggles and presses her boot harder against Anna’s face continuing to hold her sister by her hair to prevent her from moving.

After about 5 minutes of furious struggling, Anna (not getting the fresh air she needs) is too tired out to continue to resist and stops trying to get her nose away from the boot.

Nina smiles at her small victory over her sister but she notices that Anna is still holding her breath in an effort to avoid the smell.

What does Nina do?